1. Field of the Invention
The present invention relates to a down burning solid fuel, and more particularly to a down burning solid fuel body capable of almost completely eliminating the generation of noxious gas, offensive odors, and smoke.
2. Description of the Prior Art
Typically, down burning solid fuel bodies have a structure including three portions, namely, a fire-igniting layer, a fire-catching layer and a body portion. Once the fire-igniting layer is ignited with fire, the fire-catching layer catches on fire from the fire-igniting layer. As a result, the fire moves downward from the fire-catching layer to the body portion over a period of time. In this case, the fire-igniting layer should consist of easily inflammable elements whereas the fire-catching layer should consist of elements capable of holding the fire well so that it can be definitely caught by the body portion. On the other hand, the body portion should consist of elements capable of burning for a long period time while generating a sufficient amount of heat.
Meanwhile, in such a down burning solid fuel body, a considerably long time is taken for the fire to move from the fire-igniting layer to the body portion. In this case, a large amount of offensive odor or smoke may generate if the combustion involved is imperfect. Where an excessive amount of an oxidant or catalyst is added to the solid fuel, a noxious gas may generate. In some cases, there may be a danger of an explosion.
In order to solve these problems, various methods have been proposed. However, none of these methods have perfectly solved the problems.
For example, a solid fuel, which is comprised of carbon powder or sawdust mixed with an oxidant, has been known. However, this solid fuel involves the generation of a large amount of smoke and the danger of an explosion even though it has the advantage of easy ignition.
A method, wherein barium nitrate, potassium chlorate, soda acetate, potassium permanganate or calcium permanganate is added to the fire-igniting or fire-catching layer, has also been proposed. In this case, however, noxious gas is generated along with offensive odors until the fuel body completely catches on fire.